1. Field of the Invention
The present invention relates to a probe shape detection apparatus and a probe shape detection method which detect a probe shape of a flexible probe.
2. Description of the Related Art
Recently, medical instruments such as endoscopes have come to be used widely to perform procedures for examination and treatment in a body cavity.
An endoscope insertion portion shape detection apparatus is sometimes used to detect a shape of a flexible endoscope insertion portion as a probe shape by detecting a position of each of plural electromagnetic coils arranged along a longitudinal direction of the endoscope insertion portion in order to facilitate insertion into a winding body cavity such as a large intestine.
A first conventional example, namely an endoscope insertion portion shape detection apparatus disclosed in Japanese Patent Application Laid-Open Publication No. 2008-119260, is configured to measure a moving speed of a source coil placed on a most proximal side of source coils serving as plural electromagnetic coils which generate magnetic fields by being arranged in a longitudinal direction of an endoscope insertion portion.
The first conventional example discloses a technique for controlling a display period of insertion aid information used to support insertion operation of the endoscope insertion portion, according to the source coil moving speed by setting a correction coefficient used to correct a time during which the insertion aid information is displayed, based on results of the measurement.
Also, a second conventional example, namely an endoscope insertion portion shape detection apparatus disclosed in Japanese Patent Application Laid-Open Publication No. 2003-245243, is configured to detect noise in plural frequency groups using sense coils adapted to detect positions of plural source coils arranged in an endoscope insertion portion, with the source coils stopped being driven. The second conventional example discloses a technique for driving the plural source coils with a drive signal of the frequency group containing the lowest noise based on noise detection results.